This invention relates to vehicular trailer hitches and, more particularly, to adapter apparatus for converting ball-type trailer hitches to pintle-type trailer hitches.
Trailers for construction equipment and other heavy duty trailers often use Lunette-type or Lunette-eye trailer tongues. A Lunette-type tongue includes a rigid, durable, hitch ring in the shape of a torus which is typically received over an upwardly projecting, hitch post secured to a vehicle. While the Lunette-eye tongue allows a certain amount of vertical pivoting by the trailer, the primary pivotal movement allowed is horizontal. Lunette tongues have been found advantageous especially with construction type equipment because they obviate the need for sockets and other closed hitching structure which is subject to corrosion, dirt collection, and deterioration when exposed to weather and severe operating conditions.
Prior to the present invention, it has been necessary to provide a specially fabricated pin or post for receiving the hitch ring of a Lunette-eye tongue. Since the tractor vehicle normally used to tow such equipment must often be used to pull other type trailers, some of which include socket tongues for use with ball-type trailer hitches, conversion between the post or pin and the ball-type hitch has often been inconvenient and time consuming. In certain situations, the entire trailer hitch had to be changed in order to tow trailers with different type tongues.
Moreover, rather than changing from hitch to hitch, the hitch ring of the Lunette-eye tongue was sometimes merely placed around the ball member of the ball-type hitch. In such case, the downward tongue weight of the trailer was relied upon to retain the hitch ring around the ball member without any positive retaining action. This resulted in dangerous situations in which the trailer could easily break free from the towing vehicle because nothing positively held the hitch ring on the ball member. Further, the fit between a hitch ring and ball member was sloppy often causing damage to the hitch itself.
Another problem encountered even when especially designed posts or pins were secured to a tractor vehicle was the difficulty in accommodating varying sizes of hitch rings of Lunette-eye tongues. If the pin or post was sized to fit the smallest internal diameter hitch ring, a great deal of slop or play was encountered when larger hitch rings were towed with the special hitch. Such slop or play greatly increased the wear factor and shortened the useful life of the hitch apparatus.
Thus, prior to the present invention, there was a significant need for a trailer hitch apparatus which could easily be converted between ball and socket connections for lighter duty trailers and pintle-type hitch ring connections of the type used with Lunette-eye trailer tongues for heavier duty applications. In addition, there was a need for a pintle-type hitch apparatus which could accommodate trailer tongues of varying sizes and yet still be durable, long wearing, and safe for extended periods of time.